Highly distinguishable tables and the like are demanded in medical practice in order to prevent erroneous preparation or administration of solid dosages such as tables.
There is a typical method for enhancing distinguishability by processing by engraving a tabletting tip surface to provide a letter or the like on a surface of a tablet. Such a tablet is, however, likely to have breakage at the engraved portion. Accordingly, there is developed a method of printing a letter or the like on a surface of a tablet with use of ink. Nevertheless, direct printing is not applicable to an uncoated tablet. Printing with use of ink causes defects such as variation in tone, bleeding, adhesion of undried ink to another tablet, and a blurred letter.
In order to solve these problems, WO2006/126561 discloses a method of marking a letter or a symbol by irradiating with constant laser light a surface of a tablet or the like including a composition for oral administration with change in color-inducing oxide (titanium oxide, yellow ferric oxide, or red ferric oxide) dispersed therein to aggregate particles of the change in color-inducing oxide so as to cause change in color.
Mixing change in color-inducing oxide in a composition for oral administration causes entire dispersion of the change in color-inducing oxide also inside the tablet or the like. This indicates that the tablet or the like contains a large amount of change in color-inducing oxide that is unnecessary for efficacy and effect of medicine.
Change in color-inducing oxide is desirably dispersed on a surface of a composition for oral administration. As a typical example, a tablet is produced by a compression molding machine and is then fed in a spray coater or a pan coater to be coated.
A tablet manufacturer needs to have a plurality of machines in a plant, including a spray coater or a pan coater. There is required the step of feeding tablets discharged from a compression molding machine into the spray coater or the pan coater. This causes necessity for a placement space as well as increase of production steps and a production period.
An orally disintegrating tablet is preferably produced through fewer steps because it is likely to chip more easily than an ordinary tablet.
Moreover, an orally disintegrating tablet being coated may deteriorate in collapsibility. Such deterioration in collapsibility occurs to a tablet having sugar coating as well as to a tablet having film coating.
JP 2012-35289 A discloses a method of producing a coated product with use of a compression molding machine, the method including the steps of: spraying to apply lubricant to an upper punch, a lower punch, and an inner surface of a die bore; spraying to apply a coating agent thereonto; filling a powdery material in the die bore; and compressing the powdery material with use of the upper punch and the lower punch. This production method achieves coating on an orally disintegrating tablet with no use of any additional machine such as a spray coater or a pan coater. There is thus caused no problem such as necessity for a placement space or increase of production steps.
JP 2012-35289 A, however, neither discloses nor suggests spraying a light coloring substance such as titanium oxide in the process of obtaining a molded product with use of the compression molding machine. There is no disclosure or suggestion of coloring the molded product by applying light.